Laroy s



(Ho Model.)

L. S. STARRETTBZ; O. P. PAY.

SURFACE GAGE No. 556,703. Patented Mar. 1'7, 1896.

Fig.4.

VIII/I UNITED STATES PATENT UFFICE.

LAROY S. STARRETT AND CHARLES P. FAY, OF ATHOL, MASSACHUSETTS, ASSIGNORS TO SAID STAR-RETT.

SURFACE-GAG E.

SPECIFICATION forming part of Letters Patent No. 556,703, dated March 17, 1896.

Application filed February 6, 1893. serial No. 461,152. (No model.)

To (LZZ whom, it rim-y concern.-

Be it known that we, LAROY S. STARRETT and CHARLES P. FAY, of Athol, in the county of lVorcester and State of Massachusetts,have jointly invented certain new and useful Improvements in Surface-Gages, of which the following, taken in connection with the ac companying drawings, is a specification.

The object of this invention is to provide a surface-gage of more universal ad justability than those heretofore known.

The features embraced in our present improvements relate to the base and to a bracket connected thereto in which the standard is mounted which supports the arm or pointer. The base is a metallic block, marginally smooth-bottomed, but preferably recessed centrally, as shown, and having at the center of its upper surface a vertical projection with parallel sides and about semicircular at its top, forming a tired hub, on which the bracket has a limited movement. The under side of the bracket is hollowed out to receive this projection and a transverse pin pivots the one to the other. The bottom of the bracket is slightly convex, so that it may have arocking motion on its pivot. A spring is introducedbetween one on d of the rocking bracket and the base, while an adjusting screw through the opposite end bears on the top of the base. By these devices the standard, which is mounted in a rotatable transverse arm or short shaft on the bracket, may be ad justed to a nicety after being approximately set and locked frictionally to the bracket by a nut on the threaded stem of said short shaft. \Vhen desired the standard may be removed and the pointer introduced through another socket in such shaft. lVe also furnish gagepins, which may protrude through the bottom of the base as a guide in setting the tool, or may be raised so as not to thus protrude, be ing held in either position by yielding devices working through lateral perforations and pressing against the sides of said pins, which preferably have grooves around them.

In the drawings, Figure l is a perspective view of our improved surface-gage. Figs. 2 and 3 are vertical sections through the base and rocking bracket in planes at right angles to each other. Fig. i is a sectional detail showing the preferred device for holding the gage-pins.

A represents the base of ourimproved gage, a flat-bottomed rectangular casting recessed underneath so as to rest marginally by its lower edges on any fiat surface.

B, Figs. 2 and 3, is a vertical hub cast integral with the base and projecting upwardly from its center.

G is a rocking bracket, hollowed out centrally to receive the hub B of the base, to which it is pivoted by a pin D. The bottom of the bracket is crowningior convex, so that it may have a limited rocking movement on its pivot, effected by an adjusting-screw E extending vertically through one end of the bracket and bearing upon the base A, and by a spring F interposed between the base and the opposite end of the bracket. (See Fig. 2.)

The cylindrical standard H is mounted in va short horizontal shaft G, which has its bearin gs in the upwardlyextending wings c of the bracket 0, between which the foot of the standard moves freely. The body of the shaft G is of greater diameter than the standard II and works in an enlarged perforation in one of the wings; but its other end 9 is much reduced in diameter, extends through and has a bearing in the other wing, and is threaded at the tip to receive a thumb-nut L.

Between the wings a notched ring K and a flattened disk-spring R surround the shaft G, the notch of such ring fitting against the side of the standard, and the spring being interposed between the ring and the adjacent wing. (See Fig. Tightening the nut L therefore draws the body G of the shaft, the standard H erected therein, and the notched ring K against such interposed spring R and holds the standard erect or at any angle to the vertical with a firm but elastic grip.

The pointer J is mounted in a bracket I, adapted to slide vertically on and revolve about the standard H, and furnished with a clamping-screw i to fix the parts in place, when either end of the pointer is brought into contact with the surface to be gaged. An approximately correct position is quickly indicated and the standard and pointer locked in place by their nuts L and 'i; then the nice adjustment requisite for the most accurate work may be effected by partial rotation of the adjusting-screw E, whereby the bracket (3 and the parts mounted thereon are tilted or slightly oscillated on the pivot-pin D. To avoid any lateral play or backlash at this point a set-screw M is introduced centrally through the bottom 'of the base, bearing by its tip against the side of the pivot to hold it firmly.

In some cases the standard 11 may be removed and the pointer J introduced through a corresponding perforation in the shaft G, as indicated in dotted lines in Fig. 1, its position being adapted to adjustment by means of the screws L and E, as will be understood.

We provide gage-pins N N extending vertically through the base A and adapted to project below its fiat bottom, when desired, in order to set the gage from the walls of a groove or from an edge below the bottom of the instrument. In Figs. 1 and 2 these pins protrude above the base, while in Fig. at they extend below it. They are held in either case by spring-pressed studs 0, adjusted by screws P in horizontal perforations in the base or by equivalent means, the tip of each stud being shown as entering a groove around the pin to hold it in either of its positions, as will be clear from Fig. 4. By simple endwise pressure on the pins they are raised or lowered, the springs yielding sufficiently to permit the sliding movement from one groove to the other. hen the instrument is to be used or set with relation to any part above the surface on which it stands, its rectangula'r outlines afford a sufficient guide, and the pins N N are dorm ant in their raised position.

\Ve claim as our joint invention- 1. The base A having a marginallyflat botto1n,and the rocking bracket 0 c pivoted thereto, in combination with the adj Listing-screw E and spring F connected to said bracket and bearing on said base, and with the standard or pointer a'djustably connected with said bracket, substantially as set forth.

2. The base A with its rigid hub B, the bracket 0 c c united to said hub by the pivot D, and the screw E and spring F for adjusting the position of the bracket with relation to the base, in combination with the rotatable shaft G g mounted horizontally in the wings c c of said bracket, the locking-nut I. engaging the threaded end 9 of the shaft, and the standard or pointer mounted in a perforation in said shaft, substantially as set forth. v

3. The fiat-bottomed base centrally recessed and having an upturned hub, and therocking bracket pivoted thereto with means of adjustment as described, in combination with the transverse shaft Gnotched ring K, spring R, and locking-nut L, and with the standard mounted on said shaft and the pointer adjustably connected to the standard, substantially as set forth.

In testimony whereof we have signed our names to this specification, in the presence of two subscribing witnesses, on this 18th dav of January, A. D. 1893.

LAROY S. STARRETT.

CHARLES P. FAY. \Vitnesses ANDREW J. HAMILTON, MINERVA R. PITTS. 

